In an Evolved Universal Terrestrial Radio Access Network (E-UTRAN), cells of different coverage sizes are deployed to improve cell coverage or to offload traffic. In an E-UTRAN network, small cells (e.g., pico cells, relay cells, or femto cells) are deployed with overlaid macro cells. A network including large cells (e.g., macro cells) and small cells (e.g., pico cells, relay cells, femto cells) is referred to as a heterogeneous wireless communication network or, for simplicity, as a heterogeneous network.
The macro cell and small cells may operate in different frequencies. For example, in a heterogeneous network consisting of macro cells and pico cells, the macro cells may operate on one frequency while the pico cells may operate on another frequency. Operating the macro cells and pico cells on different frequencies helps to reduce the interference among cells. A user equipment (UE) may be connected with a macro cell and a small cell simultaneously to benefit from services provided by both types of cells.